scholarly journals Environments with a high probability of incompatible crosses do not select for mate avoidance in spider mites

2018 ◽  
Author(s):  
Leonor R Rodrigues ◽  
Flore Zélé ◽  
Inês Santos ◽  
Sara Magalhães

AbstractArthropods are often infected withWolbachiainducing cytoplasmic incompatibility (CI), whereby crosses between uninfected females and infected males yield unviable fertilized offspring. Although uninfected females benefit from avoiding mating withWolbachia-infected males, this behaviour is not present in all host species. Here we measured the prevalence of this behaviour across populations of the spider miteTetranychus urticae. Females from five populations originally fully infected withWolbachiashowed no preference, possibly because they did not face the choice between compatible and incompatible mates in their environment. Hence, to determine whether this behaviour could be selected in populations with intermediateWolbachiainfection frequency, we performed 15 generations of experimental evolution of spider-mite populations under i) fullWolbachiainfection, ii) no infection, or iii) mixed infection. In the latter selection regime, where uninfected females were exposed to infected and uninfected males at every generation, mating duration increased relative to the uninfected regime, suggesting the presence of genetic variation for mating traits. However, mate choice did not evolve. Together, these results show that CI-inducingWolbachiaalone does not necessarily lead to the evolution of pre-copulatory strategies in uninfected hosts, even at intermediate infection frequency.

Author(s):  
Miguel Alfredo Cruz ◽  
Sara Magalhaes ◽  
Elio Sucena ◽  
Flore Zele

Wolbachia are widespread maternally-inherited bacteria suggested to play a role in arthropod host speciation through induction of cytoplasmic incompatibility, but this hypothesis remains controversial. Most studies addressing Wolbachia-induced incompatibilities concern closely-related populations, which are intrinsically compatible. Here, we used three populations of two genetically differentiated colour forms of the haplodiploid spider mite Tetranychus urticae to dissect the interaction between Wolbachia-induced and host-associated incompatibilities, and to assess their relative contribution to post-mating isolation. We found that these two sources of incompatibility act through different mechanisms in an additive fashion. Host-associated incompatibility contributes 1.5 times more than Wolbachia-induced incompatibility in reducing hybrid production, the former through an overproduction of haploid sons at the expense of diploid daugters (ca. 75% decrease) and the latter by increasing the embryonic mortality of daughters (by ca. 49%). Furthermore, regardless of cross direction, we observed near-complete F1 hybrid sterility and complete F2 hybrid breakdown between populations of the two forms, but that Wolbachia did not contribute to this outcome. This study identifies the mechanistic independence and additive nature of host-intrinsic and Wolbachia-induced sources of isolation. It suggests that Wolbachia could drive reproductive isolation in this system, thereby potentially affecting host differentiation and distribution in the field.


ENTOMON ◽  
2020 ◽  
Vol 45 (1) ◽  
pp. 81-86
Author(s):  
Mohammad Yosof Amini ◽  
Ahamad Shah Mohammadi ◽  
Srinivasa N ◽  
Onkarappa S

False spider mites are serious pests of pomegranate and frequently cause considerable economic losses in other fruit crops as well. A field experiment conducted to evaluate eleven acaricides against Tenuipalpus aboharensis infesting pomegranate plants, revealed that wettable sulphur at 2.5 g and dicofol at 2.5 ml per litre were very effective and other acaricides viz. propargite, fenpyroximate, chlorfenapyr and buprofezin were also found effective against T. aboharensis.


Genetics ◽  
1997 ◽  
Vol 146 (2) ◽  
pp. 471-479 ◽  
Author(s):  
Michael Travisano

The effect of environment on adaptation and divergence was examined in two sets of populations of Escherichia coli selected for 1000 generations in either maltose- or glucose-limited media. Twelve replicate populations selected in maltose-limited medium improved in fitness in the selected environment, by an average of 22.5%. Statistically significant among-population genetic variation for fitness was observed during the course of the propagation, but this variation was small relative to the fitness improvement. Mean fitness in a novel nutrient environment, glucose-limited medium, improved to the same extent as in the selected environment, with no statistically significant among-population genetic variation. In contrast, 12 replicate populations previously selected for 1000 generations in glucose-limited medium showed no improvement, as a group, in fitness in maltose-limited medium and substantial genetic variation. This asymmetric pattern of correlated responses suggests that small changes in the environment can have profound effects on adaptation and divergence.


Genetics ◽  
2003 ◽  
Vol 165 (4) ◽  
pp. 2029-2038 ◽  
Author(s):  
Jason L Rasgon ◽  
Thomas W Scott

AbstractBefore maternally inherited bacterial symbionts like Wolbachia, which cause cytoplasmic incompatibility (CI; reduced hatch rate) when infected males mate with uninfected females, can be used in a program to control vector-borne diseases it is essential to understand their dynamics of infection in natural arthropod vector populations. Our study had four goals: (1) quantify the number of Wolbachia strains circulating in the California Culex pipiens species complex, (2) investigate Wolbachia infection frequencies and distribution in natural California populations, (3) estimate the parameters that govern Wolbachia spread among Cx. pipiens under laboratory and field conditions, and (4) use these values to estimate equilibrium levels and compare predicted infection prevalence levels to those observed in nature. Strain-specific PCR, wsp gene sequencing, and crossing experiments indicated that a single Wolbachia strain infects Californian Cx. pipiens. Infection frequency was near or at fixation in all populations sampled for 2 years along a >1000-km north-south transect. The combined statewide infection frequency was 99.4%. Incompatible crosses were 100% sterile under laboratory and field conditions. Sterility decreased negligibly with male age in the laboratory. Infection had no significant effect on female fecundity under laboratory or field conditions. Vertical transmission was >99% in the laboratory and ∼98.6% in the field. Using field data, models predicted that Wolbachia will spread to fixation if infection exceeds an unstable equilibrium point above 1.4%. Our estimates accurately predicted infection frequencies in natural populations. If certain technical hurdles can be overcome, our data indicate that Wolbachia can invade vector populations as part of an applied transgenic strategy for vector-borne disease reduction.


2012 ◽  
Vol 78 (20) ◽  
pp. 7480-7482 ◽  
Author(s):  
Min Yue ◽  
Robert Schmieder ◽  
Robert A. Edwards ◽  
Shelley C. Rankin ◽  
Dieter M. Schifferli

ABSTRACTA novel targeted massive parallel sequencing approach identified genetic variation in eight known or predicted fimbrial adhesins for 46Salmonellastrains. The results highlight associations between specific adhesin alleles, host species, and antimicrobial resistance. The differentiation of allelic variants has potential applications for diagnostic microbiology and epidemiological investigations.


Heredity ◽  
2006 ◽  
Vol 98 (1) ◽  
pp. 13-20 ◽  
Author(s):  
T Gotoh ◽  
H Noda ◽  
S Ito

2018 ◽  
Vol 23 (10) ◽  
pp. 2033
Author(s):  
Ivana Marić ◽  
Irena Međo ◽  
Slobodan Jovanović ◽  
Radmila Petanović ◽  
Dejan Marčić

Despite economic importance of Tetranychidae, knowledge regarding diversity of spider mites in the Balkan Peninsula and Southeast Europe is incomplete, especially in protected natural areas. This study presents diversity of spider mites (Acari: Tetranychidae) collected over five growing seasons at 296 locations in 38 protected natural areas of Serbia. A total of 31 spider mite species were found, 10 from Bryobiinae and 21 from Tetranychinae. The species Eotetranychus fagi Zacher was recorded as new to Serbia and this record was also the first one for Southeast Europe. Spider mites were found on host plants in five basic types as well as many subtypes of terrestrial habitats, with woodland as the most dominant one. A total of 151 plant species from 44 families were recorded as hosts for spider mites including new world records: 60 new hosts for family Tetranychidae and 41 new hosts for 21 spider mite species. Host plants from Rosaceae family harbored the highest number of spider mite species (16). A considerable number of species was found on host plants from the families Betulaceae (11), Asteraceae (10) and Sapindaceae (10). Two cosmopolitan spider mites, Tetranychus urticae Koch and Tetranychus turkestani Ugarov & Nikolskii, were clearly distinguished with 67 (7 new) and 43 (13 new) recorded host species, respectively; among newly recorded hosts for Tetranychidae family, these two mite species were found on 27 and 12 hosts, respectively. After the two most common species, the most striking was the presence of Bryobia praetiosa Koch with 24 (4 new) recorded host plants, followed by Amphitetranychus viennensis (Zacher), Eotetranychus carpini (Oudemans) and Bryobia rubrioculus (Scheuten), with 21 (7 new), 20 (6 new) and 16 (2 new) hosts, respectively. The remaining tetranychids were found on 1–9 host plant species. This study provided the first insight into diversity of tetranychids in Serbian protected areas. Further research in this field should focus on mites from host plants representative of specific areas and habitats, including endangered, endemic and relict species.


2002 ◽  
Vol 80 (2) ◽  
pp. 79-87 ◽  
Author(s):  
K. TRACY REYNOLDS ◽  
ARY A. HOFFMANN

In Drosophila melanogaster, the maternally inherited endocellular microbe Wolbachia causes cytoplasmic incompatibility (CI) in crosses between infected males and uninfected females. CI results in a reduction in the number of eggs that hatch. The level of CI expression in this species has been reported as varying from partial (a few eggs fail to hatch) to nonexistent (all eggs hatch). We show that male age in this host species has a large impact on the level of CI exhibited and explains much of this variability. Strong CI is apparent when young males are used in crosses. CI declines rapidly with male age, particularly when males are repeatedly mated. Wolbachia from a Canton S line that was previously reported as not causing CI does in fact induce CI when young males are used in crosses, albeit at a weaker level than in other D. melanogaster strains. The strain differences in CI expression are due to host background effects rather than differences in Wolbachia strains. These results highlight the importance of undertaking crosses with a range of male ages and nuclear backgrounds before ascribing particular host phenotypes to Wolbachia strains.


2021 ◽  
Author(s):  
Jason A Tarkington ◽  
Hao Zhang ◽  
Ricardo Azevedo ◽  
Rebecca Zufall

Understanding the mechanisms that generate genetic variation, and thus contribute to the process of adaptation, is a major goal of evolutionary biology. Mutation and genetic exchange have been well studied as mechanisms to generate genetic variation. However, there are additional processes that may also generate substantial genetic variation in some populations and the extent to which these variation generating mechanisms are themselves shaped by natural selection is still an open question. Tetrahymena thermophila is a ciliate with an unusual mechanism of nuclear division, called amitosis, which can generate genetic variation among the asexual descendants of a newly produced sexual progeny. We hypothesize that amitosis thus increases the evolvability of newly produced sexual progeny relative to species that undergo mitosis. To test this hypothesis, we used experimental evolution and simulations to compare the rate of adaptation in T. thermophila populations founded by a single sexual progeny to parental populations that had not had sex in many generations. The populations founded by a sexual progeny adapted more quickly than parental populations in both laboratory populations and simulated populations. This suggests that the additional genetic variation generated by amitosis of a heterozygote can increase the rate of adaptation following sex and may help explain the evolutionary success of the unusual genetic architecture of Tetrahymena and ciliates more generally.


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